Solvent-resistant greases for high speed bearings



3,377,284 SOLVENT-RESISTANT GREASES FDR HIGH SPEED BEARINGS Harry M. Schiefer and John S. Delphenich, Midland,

Mich., assignors to Dow Corning Corporation, Midland, Micln, a corporation of Michigan No Drawing. Filed June 7, 1965, Ser. No. 462,101 7 Claims. (Cl. 25249.6)

ABSTRACT OF THE DISCLOSURE Thermally stable lubricant greases exhibiting superior high-speed bearing life and organic solvent-resistance consisting of (a) liquid fluorinated polysiloxane and (b) arylurea thickener. Illustrative example being mixture of OSi(CHu)a This application relates to new greases that combine the desirable properties of very great resistance to solvent-washing and suflicient mechanical stability to be operative in high-speed bearings.

The lubricant greases of this invention consist essentially of a lubricant grease consisting essentially of from 60 to '90 weight percent of (a) a liquid polysiloxane of the formula (3H2 a RsSiO SIiO SIiO SlR;

OH: R a

(b) ll where R is a lower alkyl radical, x is 0 or 1, m has a value of 0 to 2, and Z is a monova-lent nitrophenyl radical, an a,oc,oz-tI'iflIlOrOtOlyl radical, an aryl radical, an alkaryl radical, a haloaryl radical where the halogen is of a lower atomic number than iodine, or a cycloalkyl radical of at least 5 carbon atoms, the free valence of Z existing on a cyclic carbon atom, and at least one-eighth of the Z groups being nitrophenyl or a,a,e-trifiuorotolyl.

The greases of this invention fall into the category known as aryl-substituted urea greases. This class of grease is disclosed in US. Patents 2,710,839; 2,710,840, and 2,710,841. None of the disclosed greases, however, possess both of the above excellent properties as do the greases of this invention.

States Patent C) Patented Apr. 9, 1968 R can be any lower alkyl radical such as methyl, ethyl, or isopropyl.

R can be any of the classes mentioned above. Examples are aryl radicals such as phenyl or xenyl; alkaryl radicals such as tolyl, ethylphenyl or propylxenyl; and haloaryl radicals such as tetrafluorophenyl, chlorophenyl, and dibromophenyl. It is desirable for the R groups to be inert and not easily cleaved from their attached silicon atoms; any organic group that fulfills these criteria is operative.

Z can be any of the classses mentioned above, e.g. haloaryl as described above, and cycloalkyl such :as cyclopentyl and cyclohexyl.

It is necessary for at least one-eighth of the Z groups to be nitrophenyl or u,a,a-trifluorotolyl A significant difference in the resistance to solvent-washing of the grease occurs when even this small fraction of the Z groups is one of the above stated radicals.

It is often preferred, however, for at least two-fifths of the Z groups to be nitrophenyl or a,a,a-trifluorotolyl.

Ingredient (a), the organopolysiloxane ingredient, is well-known and commercially available in varying viscosities. The best solvent-resistance is obtained when ingradient (a) has a viscosity at 25 C. of over 500 cs. It is preferred for b of ingredient (a) to be 1.

Ingredient (b) is a reaction product of isocyanates with primary amines. An isocyanate reacts spontaneously with a primary amine at room temperature, although moderate heating is often desirable in order to accelerate the reaction.

Ingredient (b) can be prepared in either of the followmg ways:

where the symbols are defined above.

Method (1) is generally preferred.

To prepare the grease of this invention, the reaction for preparing ingredient (b) should be performed in a manner that keeps ingredient (b) in a very finely divided state. This can be done by (1) running the reaction in the presence of at least sufiicient volatile, inert solvent to make a slurry, examples of which solvent are benzene,

toluene, diisobutylether, octane, ethylene glycol dimethyl-- The greases of this invention are also useful as sealing compositions and rubber lubricants, exhibiting the same advantage of solvent-resistance. The compositions of this invention exhibit only small changes in physical consistency upon vigorous working; they are stable at high temperatures, having generally low bleed and evaporation rates; and they generally operate in the presence of liquified gases such as liquid oxygen. These materials give excellent results when they are used as lubricants for highspeed bearings and other uses involving a great amount of shearing action.

Other additives can be present in the compositions of this application without necessarily interfering with their improved properties. Examples are pentachlorophenylmercaptoacetic acid, M08 corrosion inhibitors, and inorganic pigments in small quantifies.

The following examples are illustrative only and should not be construed as limiting the invention, which is properly delineated in the appended claims.

Example 1 (a) To 70 parts by weight of a polymer of the formula and 17.1 parts of meta-aminobenzotrifiuoride CFa The mixture was heated at 125 C. and stirred until the reaction between the latter two ingredients was complete, forming O O G h a The 1,1,1-trichloroethane was removed by heating the mixture in a vacuum at 150 C.

The resulting product was a grease having excellent physical stability, and showing little change in consistency after vigorous working.

(b) A film of the grease was placed on an aluminum panel, and the panel was partly immersed in a mixture of 60 weight percent isooctane, 5 percent benzene, 20 percent toluene, and percent xylene. The grease film remained intact on the panel for over 8 hours.

'(c) The grease was used to lubricate a 204 size bearing which was operated continuously at 10,000 r.p.m., 400 F., and a 5 pound load. The bearing operated for 941 hours before failin g.

The above bearing test was repeated, using a 197 pound load. The bearing had not failed after 675 hours of operation.

(GHa)sSiO Example 2. To 83.4 parts by weight of a polymer of the formula CH3 (CHzDaSiO S iO HiCFz I1 having a viscosity of 1460 cs. at 25 C., there was added 80.2 parts of 1,1,1-trichloroethane, 8.02 parts of 5.16 parts of meta-aminobenzotrifluoride, and 3.42 parts of paratoluidine. The mixture was heated at 125 C. and stirred until the reaction between the latter three ingredients was complete, yielding a compound of the average formula:

The 1,1,l-trichloroethane was then removed by heating the composition at 150 C. in a vacuum.

The resulting product was a grease having excellent physical stability, and showing little change in consistency after vigorous working.

A film of the grease was placed on a steel panel and partly immersed in the solvent mixture of Example 1. The grease film remained intact on the panel for over 8 hours.

The grease was subjected to the hearing test of Example 1 at a 197 pound load. The bearing operated in excess of 1082 hours.

Example 3 To 68.1 parts by weight of a polymer of the formula Hah I E 2 Si(CHa) having a viscosity of cs. at 25 C., there was added 137 parts of 1,1,1-trichloroethane, 13.7 parts of and 18.2 parts of meta-aminobenzotrifiuoride. This was stirred and heated at C. until the reaction of the latter two ingredients was complete. Then the mixture was heated in a vacuum at C. to remove the 1,1,1- trichloroethane.

The product was a grease having good mechanical and physical stability. The grease was tested for solvent resistance in the manner of Example 1(b) using a kerosenetype jet fuel. The grease remained on the panel for over 8 hours.

The products gives good performance when used in a bearing.

Example 4 A mixture was prepared containing 78.5 parts by weight of a polymer of the formula (CHa)zSiO i Si(OHala H: (EHzCFa n having a viscosity of 1000 cs. at 25 C., about 100 parts of 1,1,1-trichloroethane, 10.8 parts of 5.5 parts of p-nitroaniline, and 5.2 parts of p-toluidine. After reaction of the latter three ingredients was complete, yielding a composition of the average formula 0 o NOTO-NdNOGm-ONdNOCm it 1'1 1'1 .1.

the mixture was heated at 150 C. in a vacuum to remove the 1,1,1-trichloroethane.

3,37 7 ,284 5 6 The product was a grease having good physical stability ingredients went to completion, yielding a. composition of in the presence of mechanical working. the average formula Upon subject to the solvent-resistance test of Example o 1(b), the grease remained on the panel for more than 8 1] hours NON OH IIICN No:

I I I The grease gives good performance when used in a i F H H H H bearing.

Example 5 The mixture was then heated in a vacuum at 150 C. A mixture of 39.4 g. of a silicone polymer of the formula to f OH2C12 welding a grease having 9 Physi' 10 cal stablllty 1n the presence of mechanical working. F Upon subjection to the solvent-resistance test of Ex- Si0 ample 1(b), the grease remained on the panel for more (CHmSO slams) than 8 hours.

CHCF: n Example7 having a viscosity of 2000 cs. at 25 C., and 11.28 g. of when a 10 of a slhcone Polymer of the formula 8 CH3 CH CH; CH; OCNO Q1800 CF CHzCH2S iO s'io [sho] shomomor,

(I311; CH; (3112 u was heated at 177 C. until a uniform dispersion resulted. OHRCAFP to This was cooled to 110 C. and mixed with a mixture consisting of 39.4 g. of the above silicone polymer, 6.27 g. of p-nitroaniline, and 4.54 g. of p-tolnidine. This was is mixed with 1.2 g. of a composition of the average thoroughly mixed, and then heated at 450 F. for 2 hours. formula C2H5 t t ra@@rWQOMQW H H H H 01 01H, NO,

The product was a grease that exhibited no measurable in a toluene dispersion, evaporation of the toluene yields change in consistency upon vigorous mechanical working. a stable grease that exhibits resistance against washing by The thickener had the average formula: organic solvents, and which gives good performance as a bearing lubricant.

Ii i Oi FQQ F F Examples H H H H OH: OH;

When 10 g. of a silicone polymer of the formula The grease was subjected to the test of Example 1(b). is mixed with 3.5 g. of

BI CH3 II it QHQWWG QWQMQh H H j H H Br NO: OF;

CH3 C3117 It remained on the panel for more than 8 hours. The in a dipropylether dispersion, evaporation of the ether grease was tested in a bearing in the manner of Example yields a stable grease that exhibits resistance against l-(c), using a load of 5 pounds. The bearing did not fail washing by organic solvents, and which gives good perin 521 hours of continuous operation. formance as a bearing lubricant.

Example 6 That which is claimed is:

1. A lubricant grease consisting essentially of from 60 to A mixture of 46.5 g. of a silicone polymer of the 9() i h percent f formula (a) a liquid polysiloxane of the formula a on so j S(CH) 3 a 1 (EH: 1 33 (EH3 (3H3 CHzOF; 11 R3810 sio:siR, having a viscosity of 625 cs., 100 g. of CH Cl 3.93 g. of a fiuoroaniline, and 5.22 g. of nitroaniline was added with HRCbFZbH n stirring to a mixture of 8.2 g. of

ONCGCHrO-CNO Where R is selected from the group consisting of the methyl radical, CH CH C F radicals, aryl radiand 100 cc. of CH Cl The mixture was allowed to stand cals, alkaryl radicals, and haloaryl radicals where the for a few hours until the reaction of the latter three halogen is of a lower atomic number than iodine, b

has an average value of 1 to 12, and n and a are 5. The grease of claim lwhere (b) is numbers selected to yield a material having a viscosity 0 at 25 C. of 75 to 30,000 cs., said liquid polysiloxane g AI having at least a 30 weight percent fluorine content; 1

H H H H (bghickened with from 10 to 40 weight percent of OH: H: H N o,

(CH) 6. The grease of claim 1 wherein (a) is 0 and (b)'is l.

7. The grease of claim 1 where (a) is 1G @w I H H H H (CHshSiO SiO siwm),

H: where R is a lower alkyl radical, x is 0 or 1, m has ()HzCF: n

a Value of 0 to and Z is a monovalant njtroPhenyl where n is of such an average value as to yield a fluid radical, an a,cx,a-trifiuorotolyl radical, an aryl radical, having a viscosity of 500 to 2000 at 5 C an alkaryl radical, a haloaryl radical, where the halogen is of a lower atomic number than iodine, or References Cited a cycloalkyl radical of at least 5 carbon atoms, the UNITED STATES PATENTS free valence being attached to a cyclic carbon atom,

and at least one-eighth of said Z groups being nitro- 2,710,830 6/1955 Swakon et a1 252' 51-5 henyl or trifluorotolyL SWakOn et a1 2. The grease of claim 1 where Z is at least 40 mol 2,710,841 6/1955 at a] 25251'5 percent a,a,a,-t1i-fiu0r0t0ly1, 2,832,739 4/ 1958 Swakon 3. The grease of claim 1 where (b) is 2,390,170 6/1959 Ragborg 2,894,969 7/1959 Pierce 25225 0 0 3,038,000 6/ 1962 Schmidt 25249.6 g 3,061,545 10/1962 Badger 252-28 1 I O G Y F'Q 3,133,883 5/1964 Hayne et a1 25 2--51.5 H N H H 3,148,883 9/1964 Fassnacht 25249.6 30 3,251,774 5/1966 Borg et al. 252-515 4. The grease of claim 1 where (b) is OTHER REFERENCES Synthetic Lubricants, by Gunderson et al., Reinhold 0 0 Pub. Corp., New York, 1962, pages 275, 277, 278, 283,

N'N CH g 290, 303 and 317. g a 1': ,1, DANIELE. WYMAN, Primary Examiner.

CHa OF: I. VAUGHN, Assistant Examiner. 

